<?php
// Smart Image Resizer 1.4.1
// Resizes images, intelligently sharpens, crops based on width:height ratios, color fills
// transparent GIFs and PNGs, and caches variations for optimal performance

// Created by: Joe Lencioni (http://shiftingpixel.com)
// Date: August 6, 2008
// Based on: http://veryraw.com/history/2005/03/image-resizing-with-php/

/////////////////////
// LICENSE
/////////////////////

// I love to hear when my work is being used, so if you decide to use this, feel encouraged
// to send me an email. Smart Image Resizer is released under a Creative Commons
// Attribution-Share Alike 3.0 United States license
// (http://creativecommons.org/licenses/by-sa/3.0/us/). All I ask is that you include a link
// back to Shifting Pixel (either this page or shiftingpixel.com), but don?t worry about
// including a big link on each page if you don?t want to?one will do just nicely. Feel
// free to contact me to discuss any specifics (joe@shiftingpixel.com).

/////////////////////
// REQUIREMENTS
/////////////////////

// PHP and GD

/////////////////////
// PARAMETERS
/////////////////////

// Parameters need to be passed in through the URL's query string:
// image                absolute path of local image starting with "/" (e.g. /images/toast.jpg)
// width                maximum width of final image in pixels (e.g. 700)
// height               maximum height of final image in pixels (e.g. 700)
// color                (optional) background hex color for filling transparent PNGs (e.g. 900 or 16a942)
// cropratio    (optional) ratio of width to height to crop final image (e.g. 1:1 or 3:2)
// nocache              (optional) does not read image from the cache
// quality              (optional, 0-100, default: 90) quality of output image

/////////////////////
// EXAMPLES
/////////////////////

// Resizing a JPEG:
// <img src="/image.php/image-name.jpg?width=100&amp;height=100&amp;image=/path/to/image.jpg" alt="Don't forget your alt text" />

// Resizing and cropping a JPEG into a square:
// <img src="/image.php/image-name.jpg?width=100&amp;height=100&amp;cropratio=1:1&amp;image=/path/to/image.jpg" alt="Don't forget your alt text" />

// Matting a PNG with #990000:
// <img src="/image.php/image-name.png?color=900&amp;image=/path/to/image.png" alt="Don't forget your alt text" />

/////////////////////
// CODE STARTS HERE
/////////////////////


if (!isset($_GET['image']))
{
	header('HTTP/1.1 400 Bad Request');
	echo 'Error: no image was specified';
	exit();
}

define('MEMORY_TO_ALLOCATE',    '100M');
define('DEFAULT_QUALITY',               90);
define('CURRENT_DIR',                   dirname(__FILE__));
define('CACHE_DIR_NAME',                '/cache/');
define('CACHE_DIR',                             CURRENT_DIR . CACHE_DIR_NAME);
define('DOCUMENT_ROOT',                 $_SERVER['DOCUMENT_ROOT']);

// Images must be local files, so for convenience we strip the domain if it's there
$image                  = preg_replace('/^(s?f|ht)tps?:\/\/[^\/]+/i', '', (string) $_GET['image']);

// For security, directories cannot contain ':', images cannot contain '..' or '<', and
// images must start with '/'
if ($image {0} != '/' || strpos(dirname($image), ':') || preg_match('/(\.\.|<|>)/', $image))
{
	header('HTTP/1.1 400 Bad Request');
	echo 'Error: malformed image path. Image paths must begin with \'/\'';
	exit();
}

// If the image doesn't exist, or we haven't been told what it is, there's nothing
// that we can do
if (!$image)
{
	header('HTTP/1.1 400 Bad Request');
	echo 'Error: no image was specified';
	exit();
}

// Strip the possible trailing slash off the document root
$docRoot        = preg_replace('/\/$/', '', getcwd());

if (!file_exists($docRoot . $image))
{
	header('HTTP/1.1 404 Not Found');
	echo 'Error: image does not exist: ' . $docRoot . $image;
	exit();
}

// Get the size and MIME type of the requested image
$size   = GetImageSize($docRoot . $image);
$mime   = $size['mime'];

// Make sure that the requested file is actually an image
if (substr($mime, 0, 6) != 'image/')
{
	header('HTTP/1.1 400 Bad Request');
	echo 'Error: requested file is not an accepted type: ' . $docRoot . $image;
	exit();
}

$width                  = $size[0];
$height                 = $size[1];


$maxWidth               = (isset($_GET['width'])) ? (int) $_GET['width'] : 0;
$maxHeight              = (isset($_GET['height'])) ? (int) $_GET['height'] : 0;

if (isset($_GET['resize'])) {
	list($maxWidth,$maxHeight)=explode('x',$_GET['resize']);
}
elseif(isset($_GET['resizefit'])) {
	list($maxWidth,$maxHeight)=explode('x',$_GET['resizefit']);
	$_GET['cropratio']=$maxWidth.':'.$maxHeight;
}

if (isset($_GET['color']))
	$color          = preg_replace('/[^0-9a-fA-F]/', '', (string) $_GET['color']);
else
	$color          = FALSE;

// If either a max width or max height are not specified, we default to something
// large so the unspecified dimension isn't a constraint on our resized image.
// If neither are specified but the color is, we aren't going to be resizing at
// all, just coloring.
if (!$maxWidth && $maxHeight)
{
	$maxWidth       = 99999999999999;
}
elseif ($maxWidth && !$maxHeight)
{
	$maxHeight      = 99999999999999;
}
elseif ($color && !$maxWidth && !$maxHeight)
{
	$maxWidth       = $width;
	$maxHeight      = $height;
}

// If we don't have a max width or max height, OR the image is smaller than both
// we do not want to resize it, so we simply output the original image and exit
if ((!$maxWidth && !$maxHeight) || (!$color && $maxWidth >= $width && $maxHeight >= $height))
{
	$data   = file_get_contents($docRoot . '/' . $image);

	$lastModifiedString     = gmdate('D, d M Y H:i:s', filemtime($docRoot . '/' . $image)) . ' GMT';
	$etag                           = md5($data);

	doConditionalGet($etag, $lastModifiedString);

	header("Content-type: $mime");
	header('Content-Length: ' . strlen($data));
	echo $data;
	exit();
}

// Ratio cropping
$offsetX        = 0;
$offsetY        = 0;

if (isset($_GET['cropratio']))
{
	$cropRatio              = explode(':', (string) $_GET['cropratio']);
	if (count($cropRatio) == 2)
	{
		$ratioComputed          = $width / $height;
		$cropRatioComputed      = (float) $cropRatio[0] / (float) $cropRatio[1];

		if ($ratioComputed < $cropRatioComputed)
		{ // Image is too tall so we will crop the top and bottom
			$origHeight     = $height;
			$height         = $width / $cropRatioComputed;
			$offsetY        = ($origHeight - $height) / 2;
		}
		else if ($ratioComputed > $cropRatioComputed)
		{ // Image is too wide so we will crop off the left and right sides
			$origWidth      = $width;
			$width          = $height * $cropRatioComputed;
			$offsetX        = ($origWidth - $width) / 2;
		}
	}
}

// Setting up the ratios needed for resizing. We will compare these below to determine how to
// resize the image (based on height or based on width)
$xRatio         = $maxWidth / $width;
$yRatio         = $maxHeight / $height;

if ($xRatio * $height < $maxHeight)
{ // Resize the image based on width
	$tnHeight       = ceil($xRatio * $height);
	$tnWidth        = $maxWidth;
}
else // Resize the image based on height
{
	$tnWidth        = ceil($yRatio * $width);
	$tnHeight       = $maxHeight;
}

// Determine the quality of the output image
$quality        = (isset($_GET['quality'])) ? (int) $_GET['quality'] : DEFAULT_QUALITY;

// Before we actually do any crazy resizing of the image, we want to make sure that we
// haven't already done this one at these dimensions. To the cache!
// Note, cache must be world-readable

// We store our cached image filenames as a hash of the dimensions and the original filename
$resizedImageSource             = $tnWidth . 'x' . $tnHeight . 'x' . $quality;
if ($color)
	$resizedImageSource     .= 'x' . $color;
if (isset($_GET['cropratio']))
	$resizedImageSource     .= 'x' . (string) $_GET['cropratio'];
$resizedImageSource             .= '-' . $image;

$resizedImage   = md5($resizedImageSource);

$resized                = CACHE_DIR . $resizedImage;

// Check the modified times of the cached file and the original file.
// If the original file is older than the cached file, then we simply serve up the cached file
if (!isset($_GET['nocache']) && file_exists($resized))
{
	$imageModified  = filemtime($docRoot . $image);
	$thumbModified  = filemtime($resized);

	if ($imageModified < $thumbModified) {
		$data   = file_get_contents($resized);

		$lastModifiedString     = gmdate('D, d M Y H:i:s', $thumbModified) . ' GMT';
		$etag                           = md5($data);

		doConditionalGet($etag, $lastModifiedString);

		header("Content-type: $mime");
		header('Content-Length: ' . strlen($data));
		echo $data;
		exit();
	}
}

// We don't want to run out of memory
ini_set('memory_limit', MEMORY_TO_ALLOCATE);

// Set up a blank canvas for our resized image (destination)
$dst    = imagecreatetruecolor($tnWidth, $tnHeight);

// Set up the appropriate image handling functions based on the original image's mime type
switch ($size['mime'])
{
case 'image/gif':
	// We will be converting GIFs to PNGs to avoid transparency issues when resizing GIFs
	// This is maybe not the ideal solution, but IE6 can suck it
	$creationFunction       = 'ImageCreateFromGif';
	$outputFunction         = 'ImagePng';
	$mime                           = 'image/png'; // We need to convert GIFs to PNGs
	$doSharpen                      = FALSE;
	$quality                        = round(10 - ($quality / 10)); // We are converting the GIF to a PNG and PNG needs a compression level of 0 (no compression) through 9
	break;

case 'image/x-png':
case 'image/png':
	$creationFunction       = 'ImageCreateFromPng';
	$outputFunction         = 'ImagePng';
	$doSharpen                      = FALSE;
	$quality                        = round(10 - ($quality / 10)); // PNG needs a compression level of 0 (no compression) through 9
	break;

default:
	$creationFunction       = 'ImageCreateFromJpeg';
	$outputFunction         = 'ImageJpeg';
	$doSharpen                      = TRUE;
	break;
}

// Read in the original image
$src    = $creationFunction($docRoot . $image);

if (in_array($size['mime'], array('image/gif', 'image/png')))
{
	if (!$color)
	{
		// If this is a GIF or a PNG, we need to set up transparency
		imagealphablending($dst, false);
		imagesavealpha($dst, true);
	}
	else
	{
		// Fill the background with the specified color for matting purposes
		if ($color[0] == '#')
			$color = substr($color, 1);

		$background     = FALSE;

		if (strlen($color) == 6)
			$background     = imagecolorallocate($dst, hexdec($color[0].$color[1]), hexdec($color[2].$color[3]), hexdec($color[4].$color[5]));
		else if (strlen($color) == 3)
			$background     = imagecolorallocate($dst, hexdec($color[0].$color[0]), hexdec($color[1].$color[1]), hexdec($color[2].$color[2]));
		if ($background)
			imagefill($dst, 0, 0, $background);
	}
}

// Resample the original image into the resized canvas we set up earlier
ImageCopyResampled($dst, $src, 0, 0, $offsetX, $offsetY, $tnWidth, $tnHeight, $width, $height);

if ($doSharpen)
{
	// Sharpen the image based on two things:
	//      (1) the difference between the original size and the final size
	//      (2) the final size
	$sharpness      = findSharp($width, $tnWidth);

	$sharpenMatrix  = array(
						  array(-1, -2, -1),
						  array(-2, $sharpness + 12, -2),
						  array(-1, -2, -1)
					  );
	$divisor                = $sharpness;
	$offset                 = 0;
	imageconvolution($dst, $sharpenMatrix, $divisor, $offset);
}

// Make sure the cache exists. If it doesn't, then create it
if (!file_exists(CACHE_DIR))
	mkdir(CACHE_DIR, 0755);

// Make sure we can read and write the cache directory
if (!is_readable(CACHE_DIR))
{
	header('HTTP/1.1 500 Internal Server Error');
	echo 'Error: the cache directory is not readable';
	exit();
}
else if (!is_writable(CACHE_DIR))
{
	header('HTTP/1.1 500 Internal Server Error');
	echo 'Error: the cache directory is not writable';
	exit();
}

// Write the resized image to the cache
$outputFunction($dst, $resized, $quality);

// Put the data of the resized image into a variable
ob_start();
$outputFunction($dst, null, $quality);
$data   = ob_get_contents();
ob_end_clean();

// Clean up the memory
ImageDestroy($src);
ImageDestroy($dst);

// See if the browser already has the image
$lastModifiedString     = gmdate('D, d M Y H:i:s', filemtime($resized)) . ' GMT';
$etag                           = md5($data);

doConditionalGet($etag, $lastModifiedString);

// Send the image to the browser with some delicious headers
header("Content-type: $mime");
header('Content-Length: ' . strlen($data));
echo $data;

function findSharp($orig, $final) // function from Ryan Rud (http://adryrun.com)
{
	$final  = $final * (750.0 / $orig);
	$a              = 52;
	$b              = -0.27810650887573124;
	$c              = .00047337278106508946;

	$result = $a + $b * $final + $c * $final * $final;

	return max(round($result), 0);
} // findSharp()

function doConditionalGet($etag, $lastModified)
{
	header("Last-Modified: $lastModified");
	header("ETag: \"{$etag}\"");

	$if_none_match = isset($_SERVER['HTTP_IF_NONE_MATCH']) ?
					 stripslashes($_SERVER['HTTP_IF_NONE_MATCH']) :
					 false;

	$if_modified_since = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ?
						 stripslashes($_SERVER['HTTP_IF_MODIFIED_SINCE']) :
						 false;

	if (!$if_modified_since && !$if_none_match)
		return;

	if ($if_none_match && $if_none_match != $etag && $if_none_match != '"' . $etag . '"')
		return; // etag is there but doesn't match

	if ($if_modified_since && $if_modified_since != $lastModified)
		return; // if-modified-since is there but doesn't match

	// Nothing has changed since their last request - serve a 304 and exit
	header('HTTP/1.1 304 Not Modified');
	exit();
} // doConditionalGet()

// old pond
// a frog jumps
// the sound of water

// ?Matsuo Basho

?>